1. Field of the Invention
The invention relates to a digitizing screen apparatus which may employ a mechanism for storing a plurality of graphic images in sheet form.
2. Description of the Related Art
The patent literature discloses several attempts to produce a series of stored graphic images. One early technique was to drive a patterned backdrop with respect to a plurality of small apertures. Schemes such as the foregoing are described in U.S. Pat. Nos. 1,114,267 and 1,172,360, among others.
A more recent technique is to project an image onto a patterned lens screen. U.S. Patent references discussing this type of technique include, but are not necessarily limited to, U.S. Pat. Nos. 2,432,896; 2,507,975 and 3,742,631.
Other U.S. Patents of possible interest include U.S. Pat. Nos. 1,832,894; 3,335,457; 3,237,331; 3,314,179; 3,329,475; 3,568,346; 3,686,781; 3,783,539 and 3,987,558.
In addition to the foregoing, other efforts have been made to produce digital-like displays. For example, digitized screens can be found in places such as Time Square, New York City. According to one embodiment, a field of light bulbs is controlled by an array of photocells, each actuating a single bulb on the display screen through an amplifier circuit. Movies of shadow graphs and in some cases real shadows, are cast upon the screen from a control romm behind the sign. The images projected on the photocells appear in lights on the display screen over the street.
Other, less costly efforts have been made to digitize images on a more modest scale. One device marketed under the name Channel 2000 incorporates a plurality of lenses. Another device known as Channel 1 used a single diffusing sheet and an egg crate separator.
It is also known in the prior art to produce a three dimensional image by projecting a moving picture on the front surface of a contoured screen.
A useful discussion of the design of light concentrators may be found in the book entitled THE OPTICS OF NONIMAGING CONCENTRATORS: Light and Solar Energy by W. T. Welford and R. Winston published in 1978 by Acadamic Press.
During the prosecution of my copending application, Ser. No. 630,832 the following patent references were also cited: U.S. Pat. Nos. 2,956,359; 3,918,185; 3,159,936 and 3,629,965.